Chlorinated aryl-thiazoles and process for their production



Patented Aug. 18, 1936 Herbert August Lubs and John Eltlonfifiole,Wilmington, Del., assig-nors to E 1. du Pont de Nemours & Company,Wilmington, DeL, a corporation of Delaware No Drawing. Originalapplication 'May 6, 1931,

Serial No. 535,560. Dividedand this application May, 26,1934,;Serial No.727,729

5 claims. f (omen-44) This application is a division of our copendingapplication, Serial No. 535,560,1iled May 6, 1931,

which matured into Patent No. 1,984,714 on De:-

cember 18, 1934..

This invention relates to the manufacture of chlorinated aryl thiazoles.More particularly it relates to the preparation of chlorinated arylthiazoles having the probable formula in which R and 33., represent arylradicals which may be alike or difierent .and which may containsubstituents, for example, halogen, alkyl and,

alkoxy, and m represents an integer.

This invention has for an object the-economical manufacture ofhalogenated-aryl-aminoaryl-thiazoles. Other objects are the productionof new chemical compounds, of new chemical processes and in general anadvancement of the art.

These objects are accomplished .by treating compounds having theprobable formula with chlorinating agents, wherein R and B have the samesignificance as above.

It was not to be foreseen that this treatment would result in nuclearlychlorinated aryltriazoles; for, as reported by Hunter and Styles inJournal of :the Chemioa'ljsociety (London), 1928, pp. 3023-4, and byDyson, Hunter, and Soyka in the same Journal 1929, pp. 462-465, thedirect bromination of l-amino-benzothiazoles results in some complex,yellow colored, bromine addition-compounds of the thiazole, whichreadily lose their bromine upon standing in humid air or upon raduction,or undergo nuclear rearrangement upon recrystallization from alcohol. Inour process, however, no such difficulties were experienced, but thechlorinated compound was obtained directly as a stable, white-coloredbody.

The invention will be further understood from a consideration of thefollowing specific examples in which the parts are given by weight.

Example I One hundred (100) parts of l-ortho-toluidino-3-methyl-benzo-thiazole were suspended in 400 parts of nitro-benzene and150 parts of sul phuryl chloride added to the well agitated mass. Thesolution was warmed for a few minutes at C., cooled and filtered. Theprecipitate was washed with benzene to remove the nitrobenzene. Theproduct consisted of the hydrochloride ofl-para-chloro-ortho-toluldino-3-methyl- 5-chlor-benzo-thiazole. Thevfree base was obtained from this compound by agitation with excessammonia. It is a white solid, sparingly soluble in boiling ethylalcohol, and melts at about 201:8 to 292.6 C. Its structure mostprobably corresponds to the formula Example II Twenty (20)methyl-benzo-thiazole were suspended in parts of nitrobenzene, andchlorine was passed in slowly at ordinary temperatures for eight hours(or until a test showed that the desired degreeof chlorination had beenobtained) The product was then removed by filtration an i, identified asin Example I.

As will be clear from the above examples this invention is applicable toa Wide range of start-- ins-compounds. It is particularly applicable :tothe preparation of ehlorinated aryl-aminobenzo-thiazoles especiallybenzo-thiazoles having the ,formula e GNH in each of which either orboth of the aryl radicals may be substituted. Very desirable resultshave been obtained by the chlorination of homothiazoles having theformula in which U, V, W, X, Y and Z represent members of the groupconsisting of hydrogen, alkyl and alkoxy. In particular, by chlorinatinga suspension of l-anilido-benzothiazole,l-ortho-paradichloram'lido-fi-chloro-benzothiazole may be obtained.

It is not intended that the invention be limited to the use of chlorineas a chlorinating agent since compounds producing similar effects mayparts of .L-ortho-toluidino-3-- be used as sources of availablechlorine. l II deis sited, a chlorination catalyst such as iron, iodineand the like may be used. r

A widerange of suspension agents may be used for example, nitrobenzene;nitrotoluene', acetic acid, ethylene: dichloride, sulphur dioxide andOther solvents and/or Lsomesol'ubility insome of the suspension media,

"itris intended that the term suspension as used in the. specificationand claims, be generic to, :and cover the mixture of starting compoundand the suspension medium whether a solution exists or not. 7 Pressure,may

vention abovedescribed, since it increases the I solubility. of thereacting gases in the solvents or suspension agents selected.

In the above description use hasbeenmade of r the formula of theltypeand for this reason, wherever the first mentioned 'formula is used inthespecification and claims 'it is intended that it cover the compoundregardless of the tautomericform in which it actu ally exists.

f yAs' willi'be seen fromthe above examples, the

products prepared according to -my;invention may be isolated either inbasic form or in the.

form of their hydrocihlorides fItr will be clear therefore that theprocess claimshereunder are 7 'initended to cover any process comprisingthe particular steps'-therein-'set fort h regardless whetheritheultimate object of the process'is to prepare the free 'bas'eiorm'oi thereactionproductor a salt thereof. a a {Ifhe compounds abovedescribed-are valuable asf intermediates in the manufacture ofdyestuils' As manyapparently widely-di'fierent embodi -ments of thisinvention may be made wi thout departing from the' spirit and scopethereof, it

be used to advantage inthe in- V 'which" comprises chlorinating asuspension of is to be understood'that we do not limit'ourselves to thespecific embodiments thereof 'ex'cept as defined in the appended claims.7

We claim: r l 1. A compound of the group consisting iof 1"- .parachloro-ortho-toluidino-3-methyl-5 chloro- 'benzothiazole and saltsthereof, the basic form' of said compound having the formula r mo andbeinga white solid, sparingly soluble in boilingethylalcohol. andmelting at about 201.8". to

; 202.6 C.'" V V x i 2. The. process of preparingl-para-chloroortho-toluidino-i3 -methyl-5- chloro-benzothiazole 1-orthotoluidino-3-methyl-benzothiazole.

'3. The process of preparing l-ortho-pa rafdi- Vchloranilido-5echloro-benzothiazole which com prises chlorinating asuspension of 'l-anilidobenzothiazole. I r V V 4. The process whichcomprises treating a1susa'test sa mple shows thatZthe-radicalR has beenchlorinated.

5. The process hich 'comprise's treating with a chlorinating agentacompound which infbasicform corresponds to the formula V in whichleitheror. both of the benzene radicals 452 are members of the group consistingof the un-' substituted phenyl radical and phenyl radicals substitutedby alkyl, alkoxy orjhalogen, said treatment with 'a chlorinatingagent'being conpension of 'a compound having theformula J v r V 30 inwhich R and R represent aryl'radicals ofthe benzene and naphthaleneseries which: i may I be alikeor difierent, witha chlorinating agentuntil}

